Container Weight FAQ

Q: The requirement is for accurate gross mass; is there a margin of error defined for this 'accuracy'?

A: As an International issue, the SOLAS regulations provide that verified gross mass shall be obtained under both Method 1 and 2 by using weighing equipment that meets the applicable accuracy standards and requirements in the State in which the equipment is being used. Those national standards and requirements will determine the acceptable level of accuracy of the weighing equipment used. There is no provision in SOLAS for any margin of error; this is a physical weighing requirement, not a system of estimation. Gross mass derived using compliant equipment and procedures will meet the legal requirements.

There is no single international weighing equipment accuracy standard at present although the International Organization of Legal Metrology has issued recommendations for various types of weighing equipment. For example, EU Directive 2004/22/EC on measuring instruments provides guidance within the European Union in relation to ‘automatic weighing instruments’. Similar guidance exists for ‘non-automatic weighing instruments’ and many countries and regions will have enacted legislation and standards to cover such equipment.

Accuracy refers to the precision with which a measurement (in this case mass) is made. Accuracy is the only concept with which the shipper need be concerned. National enforcement agents may exercise discretion or tolerance in deciding when to initiate further investigations or penalty action. However, shippers using compliant weighing devices and processes will obtain values that are well within any tolerances adopted nationally for enforcement purposes. Shippers not using compliant weighing devices and processes may be found in violation even if the gross masses that they provide fall within government enforcement tolerances.

If a shipper is merely estimating the gross mass and hoping to fall within government enforcement tolerances, it is violating the SOLAS requirements and could incur sanctions or delays pursuant to applicable national legislation. There are no exemptions from the requirement to weigh using either Method 1 or Method 2.